Study of palatal rugae pattern in gender identification

Pooja Balgi; Bhakti Bhalekar; Ketaki Bhalerao; Eesha Bhide; Sangeeta Palaskar; Pargatsingh Kathuriya

doi:10.4103/2277-4696.156519

ORIGINAL ARTICLE

Year : 2014 | Volume : 3 | Issue : 1 | Page : 13-16

Study of palatal rugae pattern in gender identification

Pooja Balgi¹, Bhakti Bhalekar¹, Ketaki Bhalerao¹, Eesha Bhide¹, Sangeeta Palaskar², Pargatsingh Kathuriya²
¹ Intern, Sinhgad Dental College and Hospital, Pune, Maharashtra, India
² Department of Oral Pathology and Microbiology, Sinhgad Dental College and Hospital, Pune, Maharashtra, India

Date of Web Publication

6-May-2015

Correspondence Address:
Dr. Pargatsingh Kathuriya
Department of Oral Pathology and Microbiology, Sinhgad Dental College and Hospital, Pune, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/2277-4696.156519

Abstract

Aim: The aim was to determine the gender differences in rugae pattern with regards to the length, number, and shape. Materials and Methods: Fifty patients (25 males, 25 females) aged 30-50 years were randomly selected from the routine outpatient department at Sinhgad Dental College and Hospital. Maxillary impressions were made using alginate hydrocolloid and cast in dental stone. Palatal rugae pattern were then evaluated under the parameters such as length, number, and shape. Results: The association of rugae pattern (length, number, shape) and the gender was analyzed using Chi-square test for qualitative variable and t-test for quantitative variable. The average length of the rugae was greater in males than in females. The average numbers of rugae were same in both males and females. Straight pattern was commonly seen in females than in males. Analysis showed significant difference with parameters like length and shape (straight pattern) in both the males and females. Conclusion: As the analysis showed significant difference with the length and shape of rugae patterns in both males and females, rugoscopy, thereby could be an important tool for gender identification. The study will be continued with larger sample size to expand knowledge about gender differences in palatal rugae patterns.

Keywords: Forensic odontology, gender, palatal rugae, rugae pattern, rugoscopy

How to cite this article:
Balgi P, Bhalekar B, Bhalerao K, Bhide E, Palaskar S, Kathuriya P. Study of palatal rugae pattern in gender identification. J Dent Allied Sci 2014;3:13-6

How to cite this URL:
Balgi P, Bhalekar B, Bhalerao K, Bhide E, Palaskar S, Kathuriya P. Study of palatal rugae pattern in gender identification. J Dent Allied Sci [serial online] 2014 [cited 2023 Jun 4];3:13-6. Available from: https://www.jdas.in/text.asp?2014/3/1/13/156519

Introduction

According to glossary of prosthodontic terms, palatal rugae is defined as an anatomical fold or wrinkle usually made in the plural sense; the irregular fibrous connective tissue ridges located in the anterior third of the hard palate. ^[1] It is also known as plica palatinae. Palatal rugae appear in the 3 ^rd month of intra-uterine life. Due to its anatomic position, rugae are protected from thermal insults by the tongue and buccal pad of fat. Rugoscopy involves the study of palatal rugae pattern for human identification. Due to the stability and uniqueness of the palatal rugae pattern, it has been considered as one of the relevant parameters for human identification in the field of forensic medicine. Palatal rugoscopy was first proposed by Trobo Hermosa in 1932. ^[2] The analysis of palatal rugae was first proposed by Allen in 1889. ^[3] Rugoscopy is useful in mass disasters where conventional methods are not feasible.

The purpose of this paper was to study the palatal rugae pattern between 25 males and 25 females aged 30-50 years. A study conducted by Lima ^[4] concluded that there are no gender differences in the morphology or arrangement of palatal rugae. The parameters considered for comparison are the length, number, and shape of the palatal rugae in this study, which were then statistically compared.

Materials and Methods

A total number of 50 (25 male, 25 female) irreversible hydrocolloid (alginate) impressions of the upper arch were made. The candidates were randomly chosen from the outpatient department of Sinhgad Dental College and Hospital. The chosen candidates were dentate and were free of congenital abnormalities, infectious disease, trauma or orthodontic treatment. The impressions were then poured using dental stone [Figure 1]. The stone models were free of voids or discrepancy especially in the anterior two-third of hard palate. The base of the stone model was trimmed parallel to the occlusal plane. The palates examined in these studies were shallow with U-shaped arch frame.

Figure 1: Maxillary impression poured in dental stone

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Method of identification

A midline was drawn coinciding with that of the mid palatine raphae extending from the incisive papillae to the posterior most extent of the rugae on the palate. This divided the rugae in two halves and the rugae in each half were highlighted using a lead pencil under spot light by four different examiners [Figure 2].

Figure 2: Rugae pattern highlighted using lead pencil

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The pattern of rugae was determined using Thomas and Kotze classification ^[5] [Figure 3]. It classifies the rugae pattern into straight, wavy, circular, curved, and unification. The shape, number, and length of rugae pattern were studied thrice for each cast by three different examiners and the mean value for length and numbers were then calculated. The length of each rugae was measured using a Yamayo Vernier Calliper in millimeters (mm) [Figure 4].

Figure 3: Thomas and Kotze classification of rugae pattern

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Figure 4: Length of rugae measured using Yamayo Vernier Calliper

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Statistical analysis

Chi-square test and t-test were used for comparison between the desired parameters.

Results

The average length of rugae was greater in males than females (males-13.63 mm females-11.66 mm) [Table 1]. Chi-square analysis showed significant difference of length in both males and females (P < 0.05) [Table 2]. The numbers of rugae were grouped as 10, <10, and >10 [Graph 1] and [Graph 2]. The Chi-square analysis did not show any significant difference in numbers of rugae in both males and females (P > 0.05) [Table 3]. The shapes of the rugae recorded were as follows: Circular, straight, curved, wavy, and unification. Combinations of all the above mentioned shapes were seen in both the males and females [Graph 3]. Of all the shape patterns, straight pattern was most commonly seen. The straight pattern was more commonly seen in females than in males [Graph 4]. Chi-square analysis showed significant difference in straight pattern in both males and females (P < 0.05) [Table 4].

Table 1: Distribution of Length of Rugae in Males and Females

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Table 2: T-Test Showing Significance of Length Difference in Males and Females

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Table 3: Chi-Square Tests for Numbers of Rugae in Both Males and Females

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Table 4: Chi-square tests showing significance for straight pattern in males and females

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Discussion

In our study, stone models are used as ante-mortem record due to simplicity in analysis and minimum fabrication cost. Due to the subjective nature of observation and interpretation in and between observers, examiners have found difficulty in the task of classification of rugae pattern. Apart from Thomas and Kotze classification used for the study, the other classification device to record the rugae pattern are Silva, Carrea, Lysell. ^[6],[7],[8] The present study investigated differences in the number, shape, and length of rugae pattern in 25 males and 25 females visiting Sinhgad Dental College and Hospital. According to our study, the average size of rugae pattern in males was 13.63 ± 2.41 and in females was 11.66 ± 2.20 [Table 1]. The study revealed the average length of rugae was significantly greater in males than females according to the t-test [Table 2]. A study conducted by Kamal et al. ^[9] concluded that the average size of rugae pattern was seen to be 10.05 ± 1.51 in both males and females with no significant difference on the right and left side of the midline. A study conducted by Nayak et al., ^[10] Kotrashetti et al., ^[11] Kumar et al., ^[12] Surekha et al., ^[13] Shanmugam et al., ^[14] Mohammed et al., ^[15] Bajracharya et al., ^[16] and Kapali et al. ^[17] showed the predominance of curved and wavy pattern of rugae in most population. In our study, straight pattern was seen to be prevalent in both the genders [Graph 4] which was statistically significant more in females [Table 4]. These findings confirms with the findings of a study conducted by Ibeachu et al. ^[18] in Ikwerre ethnic group of Nigeria. In our study, we had segregated the rugae patterns in both the genders under three categories (10, <10, >10). The Chi-square test did not show any significant difference in the number of rugae pattern in both the genders [Table 3]. According to this study, females were shown to have less number of rugae than males, which was statistically insignificant. This result contraindicates the study conducted by Bharath et al. ^[19] and Surekha et al. The result of our study confirms with the results presented by Dohke and Osato ^[20] who reported that among the Japanese the females have fewer number of rugae than males. These findings indicate some racial and gender differences in rugae patterns.

Conclusion

The most commonly seen rugae pattern in both males and females is of the straight variety. Statistically significant straight pattern was found in females. Furthermore, the average length of the rugaes was greater in males than females, which was statistically significant. Although, there was no statistically significant difference in numbers of rugae in males and females, females were found to have less numbers of rugae than males. Due to the small sample size, further research is indicated to substantiate the findings of the present studies. Examination of a larger sample size would be continued to corroborate with the findings.

Acknowledgments

We would like to thank Dr. Dheeraj Kalra (Senior lecturer, Department of Public Health Dentistry, Sinhgad Dental College and Hospital, Pune, Maharashtra, India) for his valuable contribution while performing this study

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